U.S. Pat. No. 2,902,036 discloses a disposable ostomy bag having a pre-formed opening 15b through which an internal clamping member 17 may be inserted and then frictionally connected to an outer clamping member 18. The passage through the inner clamping member is sized to provide a fluid-tight seal with the outer surface of a catheter 20 inserted therethrough. A catheter may therefore extend through the wall of the bag without disrupting the integrity of the bag as a fluid collecting device.
Problems associated with such a construction include the need for utilizing a special bag having a pre-formed opening for attachment of the clamping rings and the requirement that only catheter tubes of certain size be used if an effective seal is to be formed between the catheter and the clamping assembly. The latter problem has been reduced in commercial constructions by utilizing a gradually tapered tubular nipple formed of elastic material that may be cut anywhere along its length to form a catheter-receiving opening of selected size. However, in the use of such a product, the nipple is adhesively secured to the wall of a bag after an opening is manually formed therein. Although the use of a bag having a pre-formed single-size opening is eliminated, such a construction introduces additional complexities and problems in manually forming an opening of the proper size in the wall of a bag, insuring that the outer surface of the bag about the opening is dry so that an effective adhesive seal may be formed, adhering the nipple to that outer surface, and preferably framing the area of adhesive attachment with waterproof tape to reduce the possibilities of fluid leakage and/or detachment. Even when such precautions are taken, the possibility remains that separation along the area of adhesive attachment may occur during use.
Other patents illustrative of the state of the art are U.S. Pat. Nos. 3,893,446, 3,830,235, and 4,084,590.
Accordingly, it is an object of this invention to provide a port forming device and method which may be used with flexible thermoplastic films and, in particular, with the film materials commonly used for wound covers, surgicial covers, and pouches of the type widely available as collection appliances, and which result in a secure and highly effective leakproof attachment that dispenses with the use of adhesives and sealing agents.
Another aspect of this invention lies in providing a device and method for easily and quickly piercing an access hole in the wall of a flexible plastic film, utilizing an internal coupling ring as an element in the piercing operation, and thereafter joining an external coupling ring to the internal ring to form a fluid-tight seal with the film material. In that connection, it is a specific object and aspect of the invention to interconnect an elastomeric nipple with the external coupling ring so that when the rings are locked together the skirt portion of the nipple is not only securely anchored in place but also functions as a resilient sealing gasket between the parts and as means for absorbing shocks, preventing or reducing kinking, and, in general, stabilizing the connection between the catheter or other conduit and the plastic film through which that conduit extends.
Briefly, the access device includes an internal support ring (or coupling ring) having a side wall with an outwardly-projecting annular flange at one end thereof, a pointed piercing element with a textured surface adapted to be inserted into the support ring to form a wall-piercing assembly with that ring, a tubular nipple of elastomeric material having a proximal end dimensioned to fit about the side wall of the internal support ring and an external locking ring (or coupling ring) dimensioned to receive the side wall of the internal support ring to clamp the proximal end of the nipple, as well as the collar of thermoplastic film, between the internal and external rings, thereby securing the rings and nipple to each other, and to the pierced film, and also utilizing the elastomeric material of the nipple to provide a leakproof seal between the access device and the film. When fully assembled, the components of the access device (excluding the piercing element) latch or lock together to resist disengagement from each other and from the thermoplastic film.
In one embodiment, the tubular nipple is tapered from an enlarged proximal end to a reduced distal end, the taper preferably being incremental and composed of concentric cylindrical sections of progressively decreasing size. By cutting the nipple at a selected location along its length, the cylindrical section of smallest diameter will provide a substantial inner surface for making fluidtight sealing engagement with the outer surface of a catheter tube or other conduit.
Other features, objects, and advantages of the invention will become apparent from the specification and drawings.